WINNIPEG - A situation that officials described as volatile and dangerous began to ease late Monday as fire crews started to knock back a massive blaze at a Winnipeg warehouse holding highly explosive fuel used for car racing.

No one was hurt when fire and explosions rocked Speedway International, a company that boasts on its website it is "North America's No. 1 source for 99.99 per cent racing methanol."

By the time fireballs and huge plumes of dense, black smoke were billowing into the air, the handful of workers employed at the plant had already gone home for the day.

Soon after arriving at the conflagration, emergency crews quickly retreated due to the danger posed by the contents of the warehouse as well as nearby tanker trucks and rail cars.

"We were moved back twice, just for precaution," said Randy Hull, Winnipeg's emergency co-ordinator.

"Once you start hearing the things pop, you never know. Not everything goes up, some things go out, and if you're in that radius ... it's very unpredictable."

The caution proved warranted — throughout the evening, there were several more explosions.

"Numerous roadways in the surrounding area have been closed to all traffic," Winnipeg police said in a statement. "As a result of the fire, some evacuations in the immediate area have already occurred."

In fact, businesses and some 100 homes in an 800-metre radius were evacuated. Residents were offered shelter at a nearby curling rink and the city brought in transit buses for those who wanted to wait and see what would happen.

Hull said firefighters were aided by light winds and said the burning fuel was not toxic.

"The bonus we have is that the buildings around are quite a distance away, we're talking 100 metres ... so it wasn't going to leap-frog building-to-building."

However, police still warned people who might be tempted to come out and watch the fire to stay home.

"Emergency personnel have noted that some members of the public have made their way toward the scene due to curiosity. These individuals are requested to leave the area immediately."

Eventually, special airport fire trucks were brought in to put foam on the fire, and before long the flames looked to be subsiding.

However, officials said crews would likely continue to be on the job overnight.

Speedway International says its Pro Comp racing methanol can be shipped throughout North America in sealed 55-gallon drums via tank trucks and by rail.

"Pro Comp racing methanol will provide more horsepower, more torque and longer engine life than any other industrial grade or off-spec methanol," the company says on its website.

It says the fuel is used for drag racing and Indy car racing.

Speedway International owner Royce Rostecki made headlines a few years ago when a subsidiary of his company, Greenway Bio-diesel, became the first in the province to be licensed for production of biodiesel.